Unit 2: Energy and Matter

In Van Helmont's willow tree experiment, what was the primary variable he measured?

• Volume of water used

• Mass of the tree and soil

• Height of the tree

• Number of leaves produced

Van Helmont's experiment disproved which hypothesis about plant growth?

• Plants grow by absorbing sunlight

• Plants grow by 'eating' soil

• Plants grow by absorbing water

• Plants grow by absorbing carbon dioxide

After 5 years in Van Helmont's experiment, the tree gained approximately how much mass?

• 2.3 kg

• 74.5 kg

• 90.8 kg

• 167.6 kg

What did Joseph Priestley discover when he placed a mouse with a mint plant in a sealed jar?

• Carbon dioxide

• Nitrogen

• Oxygen

• Water vapor

Priestley called air that killed mice 'injured air.' What molecule was actually depleted?

• Carbon dioxide

• Nitrogen

• Oxygen

• Water vapor

Jan Ingenhousz's experiment with underwater plants demonstrated that:

• Plants produce oxygen only in darkness

• Plants produce oxygen only in light

• Plants consume oxygen in light

• Plants don't affect oxygen levels

According to Nicolas de Saussure's experiments, plants gain mass primarily by:

• Absorbing minerals from soil

• Absorbing water from soil

• Converting carbon dioxide to sugars

• Storing nitrogen compounds

Where do oak trees get most of their 8-ton mass from?

• Soil minerals

• Water from roots

• Carbon dioxide from air

• Nitrogen from bacteria

The quote 'Food is simply sunlight in cold storage' refers to:

• Refrigeration technology

• Energy stored in chemical bonds

• Solar panels

• Photosynthetic bacteria

What percentage of a plant's mass typically comes from soil minerals?

• Less than 1%

• About 10%

• About 25%

• More than 50%