.oxygen-calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 20px;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
color: #333;
}
.oxygen-calculator-wrapper h2 {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
}
.calc-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 15px;
}
.calc-col {
flex: 1;
min-width: 250px;
}
.calc-label {
display: block;
margin-bottom: 8px;
font-weight: 600;
font-size: 0.95rem;
}
.calc-input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
box-sizing: border-box;
}
.calc-input:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}
.calc-btn {
width: 100%;
padding: 12px;
background-color: #3498db;
color: white;
border: none;
border-radius: 4px;
font-size: 1.1rem;
cursor: pointer;
font-weight: bold;
transition: background-color 0.2s;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #2980b9;
}
.results-box {
margin-top: 25px;
background: #fff;
padding: 20px;
border-radius: 4px;
border-left: 5px solid #27ae60;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
display: none;
}
.result-item {
margin-bottom: 15px;
padding-bottom: 15px;
border-bottom: 1px solid #eee;
}
.result-item:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
font-size: 0.9rem;
color: #7f8c8d;
text-transform: uppercase;
letter-spacing: 0.5px;
}
.result-value {
font-size: 1.8rem;
font-weight: 700;
color: #2c3e50;
}
.result-unit {
font-size: 1rem;
font-weight: 400;
color: #7f8c8d;
}
.article-content {
max-width: 800px;
margin: 40px auto;
line-height: 1.6;
color: #444;
font-family: inherit;
}
.article-content h3 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.article-content ul {
background: #f0f7fb;
padding: 20px 40px;
border-radius: 5px;
}
.formula-box {
background: #2c3e50;
color: #fff;
padding: 15px;
border-radius: 5px;
font-family: monospace;
text-align: center;
margin: 20px 0;
}
.error-msg {
color: #e74c3c;
text-align: center;
margin-top: 10px;
display: none;
font-weight: bold;
}
function calculateRespirationRate() {
// Get input elements by ID (Must match HTML IDs exactly)
var distanceInput = document.getElementById('distanceMoved');
var radiusInput = document.getElementById('tubeRadius');
var timeInput = document.getElementById('timeElapsed');
var massInput = document.getElementById('organismMass');
var resultBox = document.getElementById('resultBox');
var errorDisplay = document.getElementById('errorDisplay');
// Parse values
var distance = parseFloat(distanceInput.value);
var radius = parseFloat(radiusInput.value);
var time = parseFloat(timeInput.value);
var mass = parseFloat(massInput.value);
// Reset display
errorDisplay.style.display = "none";
resultBox.style.display = "none";
// Validation
if (isNaN(distance) || isNaN(radius) || isNaN(time)) {
errorDisplay.innerHTML = "Please enter valid numbers for Distance, Radius, and Time.";
errorDisplay.style.display = "block";
return;
}
if (time <= 0 || radius 0) {
specificRate = rate / mass;
specificRateText = specificRate.toFixed(4);
} else {
specificRateText = "—";
}
// Update UI
document.getElementById('resVolume').innerHTML = volume.toFixed(3);
document.getElementById('resRate').innerHTML = rate.toFixed(3);
document.getElementById('resSpecificRate').innerHTML = specificRateText;
resultBox.style.display = "block";
}
Understanding Rate of Oxygen Uptake
The Rate of Oxygen Uptake is a critical physiological metric used to determine the metabolic rate of an organism. In aerobic respiration, organisms consume oxygen to produce energy (ATP) from glucose. By measuring how much oxygen is consumed over a specific period, scientists can deduce the metabolic activity of small invertebrates, germinating seeds, or cell cultures.
The Respirometer Setup
This calculator is designed for data derived from a respirometer. A simple respirometer typically consists of a sealed chamber containing the organism and a capillary tube containing a colored fluid (the manometer fluid). Potassium hydroxide (KOH) or soda lime is placed in the chamber to absorb the carbon dioxide ($CO_2$) produced by respiration.
Because the $CO_2$ is absorbed, any decrease in gas volume within the chamber corresponds directly to the volume of oxygen consumed. This reduction in pressure causes the fluid in the capillary tube to move toward the chamber.
How to Calculate the Rate
The calculation involves three steps, starting with the geometry of the capillary tube and ending with mass standardization.
1. Calculate Oxygen Volume ($V$)
First, determine the volume of the cylinder of liquid that moved in the capillary tube. Since the tube is a cylinder, we use the formula:
V = π × r² × d
Where:
- V = Volume of oxygen consumed ($mm^3$ or $\mu L$)
- r = Radius of the capillary tube ($mm$)
- d = Distance the meniscus moved ($mm$)
2. Calculate Absolute Rate
Once the total volume is known, divide it by the time elapsed to find the rate of consumption per minute.
Rate = V / t
3. Calculate Mass-Specific Rate
To compare metabolic rates between organisms of different sizes (e.g., a woodlouse vs. a mouse), you must normalize the data by mass.
Specific Rate = Rate / Mass (g)
Example Calculation
Imagine an experiment with the following data:
- Distance moved ($d$): 35 mm
- Capillary radius ($r$): 0.5 mm
- Time ($t$): 10 minutes
- Organism Mass ($m$): 5 grams
Step 1 (Volume):
$V = 3.14159 \times (0.5)^2 \times 35 = 27.49 mm^3$
Step 2 (Absolute Rate):
$Rate = 27.49 / 10 = 2.749 mm^3/min$
Step 3 (Mass-Specific Rate):
$Specific Rate = 2.749 / 5 = 0.55 mm^3 \cdot g^{-1} \cdot min^{-1}$
Why measure Mass-Specific Rate?
Smaller organisms typically have a higher surface-area-to-volume ratio than larger organisms. This results in a higher rate of heat loss, requiring a higher metabolic rate per gram of body tissue to maintain homeostasis. Therefore, while a mouse consumes more total oxygen than a woodlouse, the woodlouse might consume more oxygen per gram of body mass.