Here is an HTML code that includes 10 puzzles on density (theory and numericals) for class 7 students. Each puzzle comes with a "Hint" and an "Answer" button, which reveal the respective information when clicked.
HTML Code:
Density Puzzles for Class 7
Density Puzzles for Class 6
Click "Hint" or "Answer" to reveal them.
1. What is the formula for density?
Hint: It involves mass and volume.
Answer: Density = Mass / Volume
2. A cube has a mass of 300 g and a volume of 100 cm³. Find its density.
Hint: Use the formula Density = Mass / Volume.
Answer: Density = 300 g / 100 cm³ = 3 g/cm³
3. What are the units of density?
Hint: The units depend on mass and volume units.
Answer: Common units are g/cm³ or kg/m³.
4. A liquid has a mass of 400 g and a volume of 200 mL. Calculate its density.
Hint: Use Density = Mass / Volume.
Answer: Density = 400 g / 200 mL = 2 g/mL
5. What happens to the density of an object when its mass increases but volume remains the same?
Hint: Think about the density formula.
Answer: The density increases.
6. A rock displaces 50 mL of water when submerged. If its mass is 150 g, find its density.
Hint: Displacement gives the volume.
Answer: Density = 150 g / 50 mL = 3 g/mL
7. If the density of an object is less than the density of water, will it sink or float?
Hint: Compare with the density of water (1 g/mL).
Answer: It will float.
8. A substance has a mass of 5 kg and a volume of 2 m³. Find its density.
Hint: Use Density = Mass / Volume.
Answer: Density = 5 kg / 2 m³ = 2.5 kg/m³
9. How does temperature affect the density of a substance?
Hint: Think about expansion or contraction.
Answer: Density decreases with an increase in temperature as the substance expands.
10. A solid has a mass of 20 g and dimensions 2 cm × 2 cm × 5 cm. Find its density.
How to Use:
1. Save the code as an .html file (e.g., density_puzzles.html).
2. Open the file in a web browser.
3. Click on "Hint" or "Answer" to reveal the respective details.
You can modify the questions or add more by duplicating the structure of each puzzle.
Hint: First calculate the volume of the solid (Length × Breadth × Height).
Answer: Volume = 2 × 2 × 5 = 20 cm³, Density = 20 g / 20 cm³ = 1 g/cm³